Appendix G - Geotechnical Analysis - Chicago District - U.S. Army

GEOTECHNICAL DESIGN APPENDIX
APPENDIX G
INTRODUCTION
1. The study area encompasses the Upper Des Plaines River Basin and tributaries from
the headwaters at the border of Racine and Kenosha Counties, Wisconsin to just north of
I-55 and the confluence with Salt Creek in Cook County, Illinois. The purpose of this
appendix is to evaluate subsurface soil information and provide generalized geotechnical
design and related construction considerations for each project feature of the proposed
flood risk management and ecosystem restoration project.
2. During the feasibility study formulation, the preliminary plan includes four levee sites,
one reservoir site, one structure modification, one pump station, five dam removal sites,
and thirteen restoration sites. Further details of all the sites are included in the Main
Report while this appendix focuses on the levee, reservoir, pump station, and dam
removal sites. This report mentions sites that were previously considered but for various
reasons, have been eliminated from the proposed plan. The sites removed include one
levee, two reservoirs, road raises, and a bridge modification. All sites within this
Appendix are located in either Lake or Cook counties, Illinois.
Project Background
3. The Upper Des Plaines and Tributaries Feasibility Study (Des Plaines II) has been
formulated to build on the benefits achieved by the Upper Des Plaines River Flood
Damage Reduction Feasibility Study (Des Plaines I). Des Plaines II recommends a plan
that further manages flood risk on the main stem in both Illinois and Wisconsin, manages
tributary flood risk, and, in addition to flood risk management, restores and enhances
degraded ecosystems within the study area.
4. The flood risk management projects are described below:
Lake Mary Anne Pump Station (FPCI01) – Plate 1 – This site would connect Lake
Mary Anne with Dude Ranch Pond by crossing underneath Golf Road between
Reding Circle and Oak Lane in Des Plaines, IL. A pump station would pump water
from one lake to the other to reduce flooding on the banks. The site is currently
covered with landscaped lawn and trees.
Bull Creek Reservoir (BCRS02) – Plate 2 – This site was removed from the
recommended plan. This site is west of Lake Street/US 45 and south of Winchester
Road in Mundelein, IL. It is currently an undeveloped grassy, marshy area with a
few trees. The berm is anticipated to be at elevation 765 NAVD88, use a 10-foot
wide crest, and hold up to around 175 acre-feet. The reservoir bottom would be at
about 754 NAVD and the spoil would be stored on site. Structural elements would
include separate inlet and outlet structures.
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